Polycystic Kidney

What is polycystic kidney?

Polycystic kidney, more fully called polycystic kidney disease (PKD), is an inherited condition in which many fluid-filled sacs, called cysts, form in the kidneys. The kidneys are two bean-shaped organs that filter waste and extra fluid from the blood to make urine. In polycystic kidney disease, the cysts slowly grow in number and size. Over years they can crowd out healthy kidney tissue, make the kidneys much larger than normal, and gradually reduce how well they filter blood.

There are two main forms. Autosomal dominant polycystic kidney disease (ADPKD) is by far the more common type and usually causes symptoms in adulthood. Autosomal recessive polycystic kidney disease (ARPKD) is rare, is often detected before or shortly after birth, and tends to be more severe in early life. The word autosomal simply means the faulty gene is not on the sex chromosomes; dominant and recessive describe how the gene is passed down in families.

Polycystic kidney affects people of every ethnic background and both sexes. Because it is genetic, it often runs in families, although it can occasionally appear in someone with no known family history when a new gene change occurs. It is one of the more common inherited kidney conditions and a recognized cause of long-term kidney failure worldwide. In many hospitals, including Acibadem, the condition is managed by the nephrology department, which specializes in kidney disease.

Polycystic kidney symptoms

Many people with polycystic kidney have no symptoms for years, especially in the dominant form. Cysts may be present from birth but grow slowly, so problems often do not appear until the thirties, forties, or later. When polycystic kidney symptoms do develop, they commonly include:

• High blood pressure, which is often the first sign and may be found at a routine check
• Pain in the back, side, or abdomen, ranging from a dull ache to sudden sharp pain if a cyst bleeds or bursts
• Blood in the urine (hematuria), which may look pink, red, or brown
• Repeated urinary tract infections or infections within a cyst, causing fever and pain
• Kidney stones, which can cause severe cramping pain
• A feeling of fullness or a visibly enlarged abdomen as the kidneys grow
• Frequent urination, including at night
• Headaches, sometimes linked to high blood pressure
• Tiredness, swelling of the legs, nausea, or itching in later stages, when kidney function has fallen significantly

Symptoms differ by type and stage. In ADPKD, early stages are frequently silent, and the first clues may be raised blood pressure or an incidental finding on an imaging scan done for another reason. As the disease advances, pain and urinary problems become more common, and eventually signs of reduced kidney function can appear. Because cysts can also form in other organs, some people notice symptoms outside the kidneys, such as discomfort from liver cysts.

In ARPKD, the picture is quite different. Affected infants may have very large kidneys, breathing difficulties at birth, high blood pressure, and poor growth. Liver scarring (a condition called congenital hepatic fibrosis) is a common part of ARPKD and can cause its own complications in childhood. Babies with severe ARPKD may need intensive medical support soon after birth.

Causes and risk factors

Polycystic kidney causes are genetic. The disease develops because of a change, or mutation, in a gene that normally helps kidney cells grow and organize into healthy tubes. When the gene does not work properly, cells multiply abnormally and fluid collects, forming cysts.

In ADPKD, the two genes most often involved are called PKD1 and PKD2. A person needs to inherit only one changed copy of the gene, from either parent, to develop the condition. Each child of an affected parent therefore has a one-in-two chance of inheriting the gene. Changes in PKD1 tend to cause an earlier and faster course than changes in PKD2, although the pattern varies widely even within the same family.

In ARPKD, the gene involved is usually PKHD1. A child must inherit a changed copy from both parents to be affected. The parents usually carry one changed copy each and have no symptoms themselves. In this situation, each pregnancy carries a one-in-four chance of a child having ARPKD.

In a minority of cases, polycystic kidney occurs in someone with no affected relatives. This happens when a new gene change arises spontaneously, or when a parent had a mild, undiagnosed form of the disease.

Risk factors that make the condition more likely, or more likely to progress quickly, include:

• A parent, sibling, or child with polycystic kidney disease
• A known PKD1, PKD2, or PKHD1 gene change in the family
• Early onset of high blood pressure or symptoms
• Large kidney size for age, seen on imaging
• Uncontrolled high blood pressure, which can speed the loss of kidney function
• Smoking, obesity, and a high-salt diet, which are linked to faster kidney decline in general
• Male sex, which in some studies has been associated with somewhat faster progression in ADPKD

It is important to understand that polycystic kidney is not caused by diet, infection, or lifestyle. Lifestyle factors can influence how quickly the kidneys weaken, but they do not cause the cysts to form.

Polycystic kidney diagnosis

Polycystic kidney diagnosis usually combines a careful medical and family history, a physical examination, imaging of the kidneys, and laboratory tests. Genetic testing is used in selected situations.

• Ultrasound. This is the most common first test. It uses sound waves to create pictures of the kidneys and can show the number and size of cysts. It is painless and does not use radiation. Doctors often apply age-based criteria: the number of cysts needed to confirm the diagnosis in someone with a family history rises with age, because a few simple cysts can occur normally in older adults.
• CT scan or MRI. Computed tomography (CT) uses X-rays and MRI uses magnetic fields to produce detailed images. These scans can detect smaller cysts than ultrasound and are used to measure total kidney volume, which helps estimate how fast the disease is likely to progress.
• Blood tests. Measuring creatinine, a waste product, allows the doctor to calculate the estimated glomerular filtration rate (eGFR), a number that describes how well the kidneys are filtering. Blood tests also check salts and red blood cell counts.
• Urine tests. These look for blood, protein, or signs of infection.
• Blood pressure measurement. Regular readings help detect high blood pressure early.
• Genetic testing. A blood or saliva sample is analyzed for changes in PKD1, PKD2, or PKHD1. This may be recommended when imaging is unclear, when a person is young and results would affect family planning, when a relative is considering donating a kidney, or to confirm ARPKD in a child. A genetic counselor can explain the benefits and limits of testing.

Doctors may also check for problems outside the kidneys. This can include imaging of the liver, an echocardiogram (ultrasound of the heart) if a heart murmur is heard, and, for some people with a family history of brain aneurysm (a weakened, bulging blood vessel), an MRI or CT scan of the head.

Screening relatives who have no symptoms is a personal decision. Knowing early can allow blood pressure to be monitored and treated, but a diagnosis can also affect insurance, employment, and emotional well-being in some settings. Your doctor can discuss these considerations with you.

Polycystic kidney treatment options

There is currently no cure that removes cysts or reverses polycystic kidney disease. Treatment focuses on slowing the decline in kidney function, controlling symptoms and complications, and, when needed, replacing kidney function. Polycystic kidney treatment options are usually combined and adjusted over time.

Monitoring and lifestyle measures. People with early disease and good kidney function are often followed with regular check-ups, blood pressure readings, and blood and urine tests. Doctors commonly advise a low-salt diet, keeping a healthy weight, regular physical activity, not smoking, and limiting alcohol. Drinking enough water throughout the day is often recommended, as it may help reduce cyst growth and lower the risk of kidney stones, although your doctor may adjust this advice if kidney function is very low. Contact sports that risk a blow to the abdomen may need to be discussed if the kidneys are very large.

Blood pressure medication. Controlling blood pressure is one of the most important parts of care. Medicines called ACE inhibitors or angiotensin receptor blockers (ARBs) are often chosen first because they lower blood pressure and may help protect the kidneys. Target blood pressure is set individually.

Medication to slow cyst growth. Tolvaptan is a medicine that blocks the action of a hormone called vasopressin, which encourages cyst growth. In adults with ADPKD who are at risk of rapid progression, it may slow the enlargement of the kidneys and the loss of function. It causes marked thirst and frequent urination and can affect the liver, so it requires regular blood tests and is not suitable for everyone. Your doctor may discuss whether it is appropriate in your case.

Managing pain. Mild pain is often treated with acetaminophen. Doctors usually advise caution with nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, because these can harm kidney function. Persistent pain from a very large cyst may sometimes be treated by draining the cyst with a needle or by a keyhole (laparoscopic) procedure to remove its wall.

Treating infections and stones. Urinary tract and cyst infections are treated with antibiotics, sometimes for longer courses than usual because medicines penetrate cysts slowly. Kidney stones are managed with fluids, pain relief, and, if needed, procedures to break up or remove them.

Care for advanced kidney disease. As kidney function falls, treatment may include medicines for anemia (low red blood cells), bone and mineral problems, and fluid balance, along with dietary advice from a kidney dietitian.

Dialysis. When the kidneys can no longer clean the blood adequately, dialysis takes over this role. Hemodialysis filters blood through a machine, usually several times a week. Peritoneal dialysis uses the lining of the abdomen as a filter and can be done at home. Very large kidneys can sometimes make peritoneal dialysis more difficult, so the choice is individual.

Kidney transplant. A transplant, in which a healthy kidney from a living or deceased donor is placed in the body, is often considered the preferred long-term treatment for kidney failure in people who are suitable candidates. Polycystic kidney disease does not recur in the transplanted kidney. In some cases, one or both native kidneys are removed before or during transplant if they are extremely large or repeatedly infected. Transplant evaluation and surgery are carried out by specialized organ transplantation teams working together with nephrologists.

Treatment in ARPKD. Children with the recessive form may need breathing support in infancy, careful blood pressure management, nutritional support to help growth, and treatment for liver complications. Some children eventually need dialysis or a kidney transplant, and in certain cases a combined liver and kidney transplant is considered.

Living with polycystic kidney and outlook

The course of polycystic kidney varies a great deal from person to person, even within the same family. Some people keep adequate kidney function throughout a normal lifespan, while others develop kidney failure in middle age. Factors linked with faster progression include a PKD1 gene change, early high blood pressure, large kidney volume for age, and repeated episodes of blood in the urine. Doctors use imaging and blood tests over time to estimate an individual’s likely path, but predictions are never certain.

Many people with ADPKD live full, active lives for decades. Regular follow-up allows blood pressure and kidney function to be tracked and treatment adjusted. Keeping to prescribed medicines, attending appointments, following dietary advice, and avoiding medicines that stress the kidneys can all support kidney health, though they cannot guarantee a particular outcome.

Because polycystic kidney can affect other organs, your care team may watch for complications such as liver cysts, heart valve changes, pouches in the bowel wall (diverticula), and, in people with a family history, brain aneurysms. Awareness of these possibilities helps ensure they are picked up early.

A genetic diagnosis can raise emotional and family questions. Some people find genetic counseling helpful when considering having children, and options such as prenatal or preimplantation genetic testing can be discussed with specialists. Support groups and counseling may also help with the uncertainty that a long-term condition brings.

For those who reach kidney failure, dialysis and transplant are established treatments, and many people continue to work, travel, and enjoy family life. Outcomes after transplant are generally comparable to those for other causes of kidney failure, although every situation is different.

Frequently asked questions

What is polycystic kidney in simple terms?

Polycystic kidney is an inherited condition in which many fluid-filled cysts grow in the kidneys over time. As the cysts enlarge, they can damage the surrounding kidney tissue and slowly reduce the kidneys’ ability to filter waste from the blood. It is most often passed down through families, and in many people it develops gradually over many years.

What are the first polycystic kidney symptoms people notice?

The earliest sign is often high blood pressure, which may be discovered at a routine check before any other problem is felt. Other early polycystic kidney symptoms can include back or side pain, blood in the urine, and repeated urinary infections. Because early disease is frequently silent, some people are diagnosed only after a scan done for another reason.

What are the main polycystic kidney causes?

Polycystic kidney causes are genetic. In the common dominant form, a change in the PKD1 or PKD2 gene is inherited from one parent. In the rare recessive form, a change in the PKHD1 gene is inherited from both parents. Occasionally a new gene change appears in someone with no affected relatives. Diet and lifestyle do not cause the cysts, although they can influence how fast kidney function declines.

How is polycystic kidney diagnosis usually made?

Doctors usually confirm the diagnosis with an ultrasound of the kidneys, sometimes followed by CT or MRI for more detail. They also take a family history, measure blood pressure, and use blood and urine tests to assess kidney function. Genetic testing may be offered when imaging is inconclusive, when results would affect family planning, or when a relative is being assessed as a kidney donor.

What polycystic kidney treatment options are available?

Treatment aims to slow the disease and manage its effects rather than cure it. Options include blood pressure medicines, a medicine called tolvaptan for selected adults at risk of rapid progression, pain management, antibiotics for infections, and lifestyle measures such as a low-salt diet and adequate fluid intake. If the kidneys fail, dialysis or a kidney transplant can replace their function.

Can polycystic kidney be prevented or cured?

Because it is genetic, polycystic kidney cannot currently be prevented, and there is no treatment that removes existing cysts or cures the disease. However, careful management of blood pressure, appropriate medication, and healthy habits may help slow the decline in kidney function. Research into new treatments is ongoing.

Will everyone with polycystic kidney need dialysis or a transplant?

Not necessarily. The condition progresses at very different speeds in different people. Some maintain enough kidney function throughout life, while others eventually need dialysis or a transplant. Your doctor may use kidney size, genetic results, and trends in blood tests over time to estimate your likely course, but no prediction is certain.

When to see a doctor

If you have a family history of polycystic kidney, or you have noticed possible symptoms such as high blood pressure, side or back pain, or blood in your urine, it is sensible to discuss this with a doctor, who can decide whether tests are needed. People already diagnosed should keep regular follow-up appointments even when they feel well, because changes in blood pressure and kidney function often occur without symptoms.

Seek urgent medical attention if you experience any of the following red-flag warning signs:

• A sudden, severe headache unlike any you have had before, especially with a stiff neck, vision changes, weakness, or confusion, which could signal a brain aneurysm
• Fever with chills and pain in the side or back, which may indicate an infected kidney or cyst
• Heavy or persistent blood in the urine, or urine that looks like cola or red wine
• Sudden, intense abdominal or flank pain that does not ease, which can occur if a cyst bleeds or bursts
• Inability to pass urine, or passing very little urine over a day
• Chest pain, severe shortness of breath, or rapid swelling of the legs, face, or abdomen
• Confusion, drowsiness, or persistent vomiting, which can be signs of severe kidney failure
• Very high blood pressure readings accompanied by headache, blurred vision, or chest pain

These situations can be serious and often need prompt assessment in an emergency department or by an on-call kidney specialist.